MONROEVILLE, Pa.  The amateur moviemakers walk out of a coffee shop into a winter dawn, hauling a small digital camera, a tripod and a boom mike made out of a hockey stick. They're just happy to find their footage is in focus.

It's an early scene from Zack and Miri Make a Porno, opening Friday.

Zack (Seth Rogen) begins eagerly outlining his plans for the next evening's secret shoot at the coffee shop, and Miri (Elizabeth Banks) looks in wonder at her slacker-ish friend. She has never seen his ambitious side before. "It suits you," she says — and suddenly everything is different between them.

Across the parking lot, filmmaker Kevin Smith is watching the performance on a monitor, slumped in a giant coat that holds back the morning's bitter chill. He has seen this play out before, in real life.

A no-account guy gets an idea, recruits his friends for help, gets a camera and shoots a movie after hours at the place of business where he mindlessly runs a register for minimum wage. Even the hockey-stick boom mike is familiar.

"Yeah … it's totally the story of Clerks," Smith says.

Maybe more important, Zack and Miri is also totally the story of untold aspiring filmmakers who have since followed in his footsteps.

Clerks "kind of democratized filmmaking in some ways," Smith says. "The movie doesn't look like much because we were rank amateurs, but that means people watching can say, 'If this dude can do it and this counts as a movie, I want to be a filmmaker, too.' "

Clerks, which was made by Smith for $27,575, not only launched his career, but it also is often credited for inspiring a generation of do-it-yourself filmmakers as well as blazing a trail in Hollywood for nasty-and-sweet comedies.

The 40-Year-Old Virgin's Judd Apatow and Juno's Jason Reitman have cited Smith as influences. Rogen has, too, though Smith thought the actor would drop his interest in Zack and Miri after he made it big in Apatow's Knocked Up.

"I don't know why he thought that," Rogen says. "It only feels right. In a lot of ways, our comedy comes from Kevin. I have often, and Judd has also, talked about how Clerks was one of the first movies showing guys talking how we talk. It seems very simple, but it was a revelation in many ways for guys who wanted to write comedy."

Clay Nichols, a former high school theater teacher and co-author of the book Filmmaking for Teens, says Smith has sent a positive message to many aspiring filmmakers.

"Kids have seen those movies and think about them. They quote his movies all the time," he says. "And the aesthetic he used, the style of dialogue, the characters he created made filmmaking really accessible even before YouTube made it obvious you could make a short movie and have a lot of people see it. The cool thing about Kevin Smith movies is he shows that production values aren't the point — the story is."

In Zack and Miri, a couple of teenagers Smith also inspired even turn up on screen. Nick Lombardi and Chris Milan, two Pittsburgh-area high school students who post silly home-video sketches to YouTube, play obnoxious guys who take a voyeur video of Miri wearing "granny panties" as she's changing her clothes and, of course, post the footage online.

"Having those dudes on the set was kind of fun because between takes they were like, 'What's that do? How's that work?' " Smith says. "I was like, 'Oh my God, I went from being a rank amateur to being a teacher of sorts.' It made me feel really old. Good, but old."

Now that Smith is joking in Zack and Miri about his do-it-yourself past, he's on track to break his personal best at the box office.

Filmmakers such as Apatow who followed Smith's sensibility routinely cross the $100 million mark. But Kevin Smith films rarely clear $30 million. Zack and Miri could be the film to change that.

With Apatow's films, Smith says, "the only kind of comedy I know how to make became vastly more commercial than we were ever able to make it. The old standby of, 'We make 'em cheap and even though they don't gross huge, they still turn a profit' becomes, 'Hey man, you got no excuse now … because this genre is viable.' "

"It's funny that a movie with the word 'porno' in the title is Smith's most mainstream film, but it is," he says. "This is a chance for Kevin Smith to break out of that $25 million to $30 million — tops — grosses. He could go to 75, 80, or $90 million."

Smith's prediction: The word "porno" in the title and his tendency to push the limits of taste could hold him back some. And, he says, that's OK — he's not in it solely for a $100 million payday.

"If it came, I'd absolutely take it. But I am a bare-minimum kind of guy," he says with a laugh.

Really big comedies, Smith adds, "just don't go into creepy areas that I like to go into." And there's one scatological scene at the end of Zack and Miri he knows will cost him with the tamer crowd.

"A smarter man would've been like, 'I can do without the (expletive) scene,' " he says. "For me, I was like, 'it's going to turn some people off. … But it's going to make my fans go (crazy).' "

Whatever the outcome, his next movie will be a change of pace — a horror film (and partway political satire) called Red State— but he expects to stick to the scrappy filmmaking roots he says changed his life. "When I realized that I wanted to be a filmmaker, that became my passion. My demeanor completely changed, and people around me noticed," Smith says.

He goes back to the line Miri says to Zack as they emerge from that first night of filming. "Those were literally the words out of my girlfriend's mouth: 'I've never seen you be ambitious.' I was like, 'Is that what it is? It feels good.' "

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